Page:Popular Science Monthly Volume 69.djvu/258

254 the most vulnerable feature is the instability of the foundation along much of the levee line.

The efficiency of the levee system is the test of all the labor and the justification of the large expenditures. The increasing efficiency may be measured in many ways. A comparison of the number of crevasses and the total number of miles of destroyed levees with the records of previous floods is the one in general use. In 1882, 284 crevasses were recorded and 59 miles of levee were destroyed. This record has been gradually improved. In 1890, but 23 crevasses were reported and 4.25 miles of levee destroyed. In 1897, the number of crevasses increased to 49, with a loss of 8.3 miles of levee. In the 1903 flood, 9 crevasses of importance were recorded and 5 of these caused a loss of 2.1 miles of the levees. The loss of levees by caving banks was a little less than 1 per cent, of the entire contents. Last year (1904) in a period of quieter flood the percentage was over 2.5. The number of square miles of overflowed area in 1903 was.5 the mileage for 1897. There is no doubt but that the levee system as it approaches completion is being made stronger and safer. Yet each crevasse or natural break spreading the confined waters over larger areas releases the tension on the banks and to some extent prevents others from occurring. To enclose the water which has spread naturally over 29,700 square miles between two walls less than 5 miles apart and covering about one tenth of its former area is no easy task. Till the present system is completed, the possibility of a flood will be uncertain that always grave dangers may be incurred to life and property within the limits of the alluvial basin of the river.

The commissioners in their general report furnish the best proof of the increased confidence in the levees by citing the progress and growth of the Yazoo Basin since their board was created. The population of this district was 94,672 in 1880, and 195,346 in 1900. The present valuation of the basin is $42,000,000. The number of banks have increased from 2 in 1893 to 51; the mileage of railroads from 225 in 1884 to 816. The cotton production in 1879 was 185,868 bales; in 1903, 426,414. The increase in corn, peas, clover and alfalfa is reported to be even greater than that of cotton. The original timber of the basin is being cleared, and there are now large shipments of lumber, as logs, boards, staves, headings and the like. Flourishing crops are seen to-day where in former years the floods measured from 20 to 25 feet in depth. 'The Yazoo Basin is sprinkled with towns whose sites were the home of the bear and the wild cat ten years ago.'

The engineers of this district in their reports of the flood of 1903 state that about one fourth of the Yazoo Basin was under water during this flood. Two crevasses occurred, letting water into the basin. One of these, three miles below Greenville, Mississippi, was at its greatest width a breach of 3,900 feet. The water flowed back upon